Wire coil stripper and inserting device

ABSTRACT

An improved wire stripper is disclosed in several embodiments. The first embodiment is a fluted stripper having a series of vertical pins extending above a hemispherical surface. The wires to be inserted in a stator are held in proper alignment between adjacent pins. The second embodiment substitutes a series of ridges and grooves for the pins to maintain coil alignment during the insertion of the coil into the stator. A third embodiment is a hybrid of the first and second embodiment using the pins in conjunction with a series of ridges and grooves and may additionally be provided with a modified blade alignment tool which serves to distribute the forces somewhat uniformly between the several pins.

United States Patent Payne et a1.

[ 1 Aug. 22, 1972 WIRE COIL STRIPPER AND INSERTING DEVICE [72] Inventors: Stanley D. Payne; Donald E. Hill, both of Fort Wayne, Ind.; Robert G. Walker, Brighton, Mich.

[73] Assignee: lndustra Products, lnc., Fort Wayne, Ind.

[22] Filed: April 13, 1970 [21] App1.No.: 27,868

[52] US. Cl. ..29/205 R [51] Int. Cl. ..H02k 15/00 ['58] Field of Search ..29/205 R, 596

[56] References Citedg UNITED STATES PATENTS 3,525,147 8/1970 Kieffer ..29/596 2,272,263 2/ 1942 Cullin ..29/205 2,432,267 12/1947 Adamson ..29/205X 3,559,268 2/1971 Droll ..29/205 R Primary Examiner- Robert L. Spruill Attorney-Jeffers and Young [57] ABSTRACT An improved wire stripper is disclosed in several embodimentsfThe first embodiment is a fluted stripper having a series of vertical pins extending above a hemispherical surface. The wires to be inserted in a stator are held in proper alignment between. adjacent pins. The. second embodiment substitutes a series of ridges and grooves for the pins to maintain coil alignment during the insertion of the coil into the stator. A third embodiment is a hybrid of the first and second embodiment using the pins in conjunction with a series of ridges and grooves and may additionally be provided with a modified blade alignment tool which serves to distribute the forces somewhat uniformly between the several. pins.

9 Claims, 12 Drawing Figures PRIOR ART i i U1:

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A TORNEYS WIRE COIL STRIPPER AND INSERTING DEVICE BACKGROUND OF THE INVENTION This invention relates to devices for winding and inserting coils in electric motors and more particularly to an improved stripper for displacing coils from a coil placing device into the stator slots of the motor.

Modern production techniques for the fabrication of stators for electric motors are fairly well automated and a typical process might consist of the following steps. The coil for a single pole is wound on an appropriately shaped coil form and transferred to a coil placing tool. For a four pole machine, the coil placing tool would be rotated 90 with respect to the coil form and another coil would be wound on the form and transferred to the coil placing tool. This cycle would be repeated for each pole. Thus, this first stage of the process would result in four sets of coils being appropriately positioned on the coil placing tool. Auxiliary coils might be wound at a second station and also properly positioned on this coil placing tool. At a third station, these coils would then be transferred to thestator. At this third station the en tire set of coils is pushed off of the coil placing tool up through the bore of the stator and into the appropriate slots in the stator. The device which performs this pushing function is known in the art as a stripper.

Prior art strippers have the major drawback that they allow a shifting or nesting of individual turns within a coil between two blades of a coil placer tool. Within specific ratios of wire diameter to the slot or gap between two placer tooling blades, this condition may prevent, materially hamper, or substantially restrict the number of turns of wire that can besuccessfully inserted into the stator slots. Prior art strippers, when processing or inserting wire diameters greater than 55 percent of the gap formed by two blades of the coil placer tool, present two distinct drawbacks due to the allowable shifting or nesting of individual turns of wire within a coil. Wire diameters which fall within the range of 55 to 78 percent of the blade gap constitute a locking condition due to the friction generated by nesting of the turns against the sides of the blades forming the blade gap. This locking condition will materially damage the wire or jam the coil placer. Wire diameters which fall above the 78% range having coils in excess of 30 to 35 turns will experience deformation and damage to the insulation of the turns nearest the stripper due to the accumulated effects of friction.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a stripper capable of transferring coils of a large number of turns.

It is a further object of the present invention to provide a stripper capableof transferring coils of a large number of turns using wire diameters equal to or larger than 55 percent of the coil placer tooling blade gap.

It is a specific object of the present invention to provide a stripper which maintains the relative positions of a plurality of coils as well as maintaining alignment of individual turns within a coil.

It is a further object of this invention to provide a stripper which does not damage the wire during the insertion process.

The present invention contemplates several embodiments for achieving the foregoing objects. In the first embodiment, a stripper is provided with vertically extending pins and laterally extending fins. The fins are adapted to extend outwardly into the gap between two adjacent teeth of the stator, thus providing support for the coils at this point. The pins are so shaped and positioned as to hold the turns of the coil in a stacked relationship. Thus, the stripper maintains the alignment of and provides support for the coils during the insertion process. The pins are removable from the stripper so that, for example, larger pins might be substituted resulting in a smaller gap between the pins so as to accommodate a coil of smaller wire size, or in the case of a given wire size, to vary the ratio of the constant wire diameter to the blade gap. The second embodiment substitutes a head portion comprising a series of ridges and troughs, the troughs being appropriately shaped so as to hold the turns of a coil in astacked relationship similar to that achieved in the first embodiment. A third embodiment is a hybrid of the first two having a series of ridges and troughs surrounded by'a series of upstanding pins with fins extending outwardly from each gap defined by the pin. This third embodiment may additionally be provided with a modified plate alignment tool which serves to distribute forces experienced by a given pin over the entire set of pins.

Accordingly, it is a further object of the instant invention to provide a stripperwhich is adaptable to use with a wide variety of wire sizes.

It is a further object of the present invention to provide a slot, movable with respect to the stator, which supports and maintains in alignment the coils being inserted. I

It is yet another object of the present invention to provide a pin type stripper where the forces normally exerted on individual pins are distributed over all of the pins.

These and other objects and advantages of the present invention will be more clearly seen from the following detailed disclosure and accompanying drawings wherein like parts are indicated by like reference numerals.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a cross sectional view showing the disadvantages of the prior art stripper;

FIG. 2 is a perspective view showing one embodiment of the present invention;

FIG. 3 shows the stripper of FIG. 2, a stator and the coils in proper alignment;

FIG. 4 is a cross sectional view of the stripper of FIG.

FIG. 5 is a partial cross sectional view showing the stripper of FIG. 2 in a coil placing environment;

FIG. 6 is a top view of an alternate embodiment showing the coils in their proper position;

FIG. 7 is across section view of the stripper of FIG. 6 taken along 7-7;

FIG. 8 is a partial cross sectional view taken along 8- FIG. 9 is a partial cross sectional view taken along 9- FIG. 10 is a top view partially in section showing the combined pin-ridge and trough embodiment;

FIG. 1 l is a cross sectional view of the stripper of FIG. 10 taken along 11-1 1; and

FIG. 12 is a cross sectional view taken along 12-12 of FIG. 1 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, one stage of an automated coil winding and placing process is shown. A stator 1 is shown in place around a series of fingers or blades 2 which tend to hold a series of coils 3 in position during the insertion process. During this process, the stator and the fingers are fixed relative to one another and a stripper 4 moves upwardly inside the fingers forcing the coil 3 up and out into the stator slots.

When the ratio of wire diameter to blade gap is in the range of approximately 55 percent to 78 percent, the soft wire tends to deform slightly and act as a wedge with its adjacent wire. This wedging or nesting action produces side forces perpendicular to the blade surfaces which results in retarding frictional forces to the inserting process. Each wire in the coil will react in this manner and since the stripper is located and pushing from the bottom of the stack of wire, the frictional forces developed are cumulative. Thisis due to the fact that each wire develops its own frictional force and must at the same time overcome the frictional retarding force of the wire directly above it. These accumulated forces present a retarding force at the stripper and for large number of turns will materially damage the wires directly adjacent the stripper such as wires 5 and 6 in FIG. 1. It has been experimentally determined that 30 to 35 turns per slot is a practical limit in which the accumulated forces will not damage wire. It can be seen that if a slot or groove which moves with the stripper is provided for which as an example turns only can be stacked within the slot then the practical turns limit can be increased to 50-55 turns before damage to the wires once again occurs on top of the stripper. This analysis of FIG. 1 illustrates the desirability of maintaining the relative position of individual turns such as 5 and 6.

This orientation may be maintained by using a stripper having the configuration shown in FIG. 2. The stripper has a series of radially extending fins 7 having edge portions 8 which serve to force the wires outwardly into the stator. The stripper has a contoured head portion having ridges l8 and grooves or troughs 9. The bottom of the trough 9 is seen to form an extension of the edge of the fin 8. A coil is then seen to be supported by the edge of the fin 8 and inside the head portion this same coil will be supported by the base of the trough 9 at the bottom and along its sides by two adjacent ridge portions. The function of this embodiment of the invention is most readily seen in FIG. 3.

A stator 1 having teeth 11 and slots 12 is placed on a series of fingers 2. These fingers are the same as those shown in FIG. 1 and serve to hold the coils indicated generally by 13 in position prior to the step of inserting them in the stator slots. A coil 13 is supported along its two sides by the fixed fingers 2 and is supported below by the edge 8 of a corresponding fin on the movable stripper. As we move nearer to the center of the stator, this coil 13 is supported on its two sides by adjacent ridges l8 and corresponding trough 9 both of which move relative to the fingers 2. Hence, in this configuration the only sliding friction which occurs will be between the coils and the finger 2. The fingers 2 are provided with a lip portion 50 which allows the coil to pass by the edge of a tooth 11 on the stator without becoming caught or scratched by the edge of that tooth.

Turning now to FIG. 4, the stripper is shown in cross section and is seen to consist of a base portion 14 and a head portion 15. The base portion has radially extending fins 7 and is provided with a threaded hole 16 for attachment to a coil placing device. The head portion is seen to consist of a series of ridges 18 and corresponding troughs 9. The stripper is designed for use with wire of a diameter less than the width of the trough 9, but not less than 78 percent of the width of that trough. This is illustrated in FIG. 5 which shows the stripper holding a series of coils during the insertion process. v

The stripper is attached to a shaft 17 which shaft forces the stripper upwardly pulling the coils 13 up with it through the bore of a stator 1. As the stripper continues its upward motion, the fins 7 maintain the coil outward between two teeth of the stator and into its position in the slots of the stator. When the stripper reaches the top of its stroke, it then recedes downwardly leaving the coil in the stator.

' To summarize the operation of the system thus far described, consider the simplified operation of winding and placing the main or running coils in a .two pole stator. The coils 19, 20, and 21 shown in FIG. 3 and forming the coils for the first pole are wound at a remote location and then transferred to the coil placing device. If we imagine FIG. 3 with the stator 1 and the stripper absent, this coil placing device will appear merely as a series of vertically extending pins 2 and the several coils will be contained by adjacent ones of the pins. This coil placing device is then indexed a second set of coils 22, 23, and 24 would be wound on the same form and then transferred to the coil placing device. A stator l is then placed on the blades 2 and initially the coils will lie near the bottom of the coil placing device.

Returning now to FIG. 5, as the shaft 17 begins its upward movement, it will pick up and maintain in a stacked relationship the several turns of each of the coils. Thus, for example, the specific coil 22 is confined in the stripper groove 25 and is also confined between the specific fingers 26 and 27 on one hand and between fingers 28 and 29 seen in FIG. 3 on the other hand. Outside of the coil placing device, this coil 22 may take on a disoriented configuration as illustrated generally at 30. As the stripper moves up, the several coils are simultaneously forced upwardly and maintained outwardly by the fins 7 into their respective slots in the stator. The gap between two adjacent fingers may be thought of as defining a slot in which a given coil is constrained and a given coil is seen to be constrained by two such slots. The stripper then forms an extension connecting these two slots which is movable with respect to the fingers and the fins associated with those slots cause the coil to move upwardly in the slots. The wedge guides 31 function to insert a protective wedge in each of the stator slots during the insertion of the coils.

FIG. 6 illustrates an alternative embodiment of the stripper which functions similarly to the first embodiment. The second embodiment comprises a body portion having a series of vertically extending parallel pins or members 32. Thus, while the stripper of FIG. 2

defined a slot for maintaining the orientation of the coils which extended completely between corresponding fins on the stripper, this embodiment only defines such a slot immediately adjacent to the fins and allows the central portion of the coil to be unconfined. A comparison between FIGS. 3 and 6 should serve to illustrate the differences in these two embodiments, but it should be noted that FIG. 6 has deleted'the stator 1 and the fingers 2 of the coil placing tool. An illustrative finger 2 is shown in its proper orientation with respect to the fins in FIG. 8.

As illustrated in FIGS. 7 and 9, the vertically extending members or pins 32 may be removably afiixed to the stripper by means such as the dowel pins 33 and 34. These vertically extending members can be made to be removable so that they may be replaced by another set of different dimensions in order to handle various wire sizes. Thus, the lower portion 35 where the pin attaches to the base of the stripper would be the same size and shape for various pin sizes. However, the upper portion 36 would differ for differing sets of pins. Alternatively, interchangeable strippers could be utilized to accommodate various wire sizes. To understand why it is desirable to have these various sizes of pins, one must consider the concept of locking wire size.

It has been experimentally found that when trying to slide a multitum coil in a slot i.e. blade gap, such as is defined between adjacent blades, that when the wire diameter is between 55 percent and 78 percent of the slot the wire will tend to bunch up, deform and jam within the slot. Hence, wire of diameters that lie within this troublesome area cannot be used with strippers such as illustrated in FIG. 1, and the same problems manifest themselves when using a stripper such as illustrated in FIGS. 6 through 10. With this stripper, however, the problem is easily overcome by removing the pins 32 and substituting therefore pins which are slightly larger and which thus define a smaller gap than the one between the corresponding adjacent fingers or blades 2. The more stringent confinement defined by the oversize pins obviates the problem.

Such a stripper as illustrated in FIGS. 6 through 9 also eliminates the limit of the number of turns which can be inserted due to accumulated frictional forces as previously described. The vertically extending pins 32 will define a blade gap equal to or less than the blade gap defined by blades 2. This new blade gap will be located in close proximity to the gap formed by the blades 2 which will reduce if not eliminate the nesting conditions within the blade gap formed by blades 2. Also the pins 32 which are maintaining the position or single file order of the wires are moving with the stripper and wire. Therefore, no sliding action occurs between the wire and pins 32 and therefore no frictional retarding forces are developed which is the limiting factor on the number of turns to be inserted.

The astute reader will have realized by this time that while the stripper of FIG. 7 will materially increase the number of turns which may be inserted in a stator at one time it too will have an upper limit to the number to the number of turns which may be inserted can be further extended by using a removable blade alignment tool as is shown in conjunction with the embodiment of FIGS. 10, 11 and 12.

Looking first at FIG. 1 1 another embodiment of the present invention is a hybrid of the stripper shown in FIG. 2 and the one illustrated in FIG. 7. This hybrid stripper has a series of parallel elongated members 38 which correspond to the elongated members 32 of FIG. 7. The stripper of FIG. 11 also has a head portion formed by a series of ridges 37 and corresponding grooves between adjacent ridges and these ridges correspond to the ridges 18 of the embodiment of FIGS. 2 and 4. FIG. 11 also illustrates dummy elongated members 39 which merely serve to properly mate the stripper with the tooling pins 26 and 27 of FIG. 5. In addition to providing a hybrid stripper having the advantages of each of the two earlier embodiments, FIGS. 10, l l and 12 illustrate the blade alignment tool having a handle 40 to effect its placementand removal on the stripper. The blade alignment tool has a flange 41 which limits its downward travel onto'the stripper and has a contoured portion 42, which mates with the interior surfaces of the pins 38 and in conjunction with those to the contour of the base portion of the stripper. The

pins 38 again are parallel elongated members which are attached to the base of the stripper in a cantilever fashion so that the upper portions of the pins are free to bend according to the stresses applied to them. The blade alignment tool 40, 41, 42 serves to tie all of these pins together so that any stress applied to one of the pins will be somewhat uniformly distributed over the set of pins and this alignment tool, of course, serves to maintain the separation between adjacent elongated members.

In summary, the invention is seen to reside in a wire stripper which provides a series of movable slots. These slots serve to maintain the coils in their proper orientation during the process of inserting the coils into a stator. Therefore, while the invention has been described with reference to a particular embodiment, persons skilled in the art will readily recognize that modifications may be made without departing from the spirit of the invention or from the scope of the appended claims. Thus, for example, while the present invention has been illustrated primarily with respect to two pole machines, the embodiment of FIG. 7 would be usable without modification for machines with other numbers of poles. The stripper of FIG. 2, of course, may also be modified so as to be usable with a four'pole stator and of turns which may be handled. This upper limit will in that instance the ridges and grooves would take on a somewhat square configuration. As another example, certain difficulties may in some instances be involved in the use of the embodiment of FIG. 2. The coil configuration caused by the coil forms may not result in a curve which will easily fit within the trough or groove of the stripper. Also, one or more wires of the coil may become crossed thereby preventing the coil from mating properly with the troughs of the stripper. These two problems can be solved by removing the central portion of the fins so as to provide a region which will except coils with crossed wires and which is not particularly limited by the coil shape imparted by the winding forms. Accordingly, the scope of the present invention is to be measured only by that of the appended claims.

We claim:

1. In an automatic coil winding and placing machine having a plurality of fixed parallel elongated members disposed on the circumference of a circle for holding coils during insertion, an improved stripper for simultaneously driving said coils through the bore of a stator and forcing them radially outward into the stator slots comprising:

a stripper base; 7

means for maintaining in separation respective ones of a plurality of coils and for maintaining in alignment each turn within a given of said coils comprising a plurality of parallel elongated members adjacent ones of said members defining a gap there between to accommodate said coils; each of said members being removably positioned on said stripper base radially inwardly of a corresponding fixed elongate member of the machine with;

means for selectively adjusting said gap to accommodate different wire sizes;

means for moving the stripper relative to the stator so as to drive the coils through the bore of the stator; and

follower means fixedly attached to the stripper base for maintaining the coils radially outward in the stator slots.

2. A coil stripper comprising:

a base portion and a head portion;

said base portion having a substantially circular cross section in a first plane;

said base portion having a plurality of radially extending fins each lying in a plane which is perpendicular to said first plane;

said base portion having means associated therewith for attachment to a coil placing device;

said head portion comprising a plurality of parallel elongated members, each member being disposed on the periphery of a circle, the plane of the circle being parallel to said first plane, said members being so disposed with respect to said fins that a gap formed by two adjacent members forms an extension of the edge of a fin lying in the proximity of said gap.

3. In a machine for inserting wire coils in a stator the machine having a plurality of fixed parallel elongated members disposed on the circumference of a circle for holding said coils during insertion, an improved coil stripper for inserting a multiple turn coil in said stator comprising:

a base portion and a head portion; said base portion having a substantially circular cross section in a first plane and having means associated therewith for attachment to a coil placing device; said head portion also having a plurality of parallel elongated members disposed on the circumference of a circle, the plane of the circle being parallel to said first plane for maintaining the relative orientation of at least some of the individual turns of a coil during the insertion process said elongated members mounted on said head portion each being positioned radially inwardly of a corresponding fixed elongated member on the machine. 4. The coil stripper of claim 2 wherein said elongated members are removabl affixed to said head portion.

5. The coil stripper 0 claim 2 wherein sai head portion further comprises a portion interior said elongated members which is provided with a plurality of slots which serve to connect specified pairs of gaps.

6. The coil stripper of claim 2 wherein said elongated members are attached to said base portion in cantilever fashion further comprising removable alignment means adapted to maintain the separation between said elongated members remote from the point of cantilever attachment.

7. The coil stripper of claim 5 wherein said elongated members are attached to said base portion in cantilever fashion further comprising removable alignment means adapted to maintain the separation between elongated members remote from the point of cantilever at tachment.

8. The coil stripper of claim 3 wherein said elongated members are removably affixed to said head portion.

9. The coil stripper of claim 3 wherein said base portion has a plurality of radially extending fins each lying in a plane which is perpendicular to said first plane, said fins being so disposed that the edge of a fin forms a radially outward extension of the gap between two adjacent elongated members.

I I JN ITED STATES PATENT OFFICE. CERTIFICATE OF CORRECTION Patent No. 3,685,118

Dated August 22. 1972 lnventor( s)Stan1e y D. Payne, Donald E. Hill, Robert G. Walker It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 42, "The.", second occurrence, ShOtlld be This Signed and sealed this 9th iay (SEAL) Attest:

EDWARD M. FLETCHER Attesting Officer one of January 1973.

ROBERT GOTTSCHALK Commissioner of Patents 

1. In an automatic coil winding and placing machine having a plurality of fixed parallel elongated members disposed on the circumference of a circle for holding coils during insertion, an improved stripper for simultaneously driving said coils through the bore of a stator and forcing them radially outward into the stator slots comprising: a stripper base; means for maintaining in separation respective ones of a plurality of coils and for maintaining in alignment each turn within a given of said coils comprising a plurality of parallel elongated members adjacent ones of said members defining a gap there between to accommodate said coils; each of said members being removably positioned on said stripper base radially inwardly of a corresponding fixed elongate member of the machine with; means for selectively adjusting said gap to accommodate different wire sizes; means for moving the stripper relative to the stator so as to drive the coils through the bore of the stator; and follower means fixedly attached to the stripper base for maintaining the coils radially outward in the stator slots.
 2. A coil stripper comprising: a base portion and a head portion; said base portion having a substantially circular cross section in a first plane; said base portion having a plurality of radially extending fins each lying in a plane which is perpendicular to said first plane; said base portion having means associated therewith for attachment to a coil placing device; said head portion comprising a plurality of parallel elongated members, each member being disposed on the periphery of a circle, the plane of the circle being parallel to said first plane, said members being so disposed with respect to said fins that a gap formed by two adjacent members forms an extension of the edge of a fin lying in the proximity of said gap.
 3. In a machine for inserting wire coils in a stator the machine having a plurality of fixed parallel elongated members disposed on the circumference of a circle for holding said coils during insertion, an improved coil stripper for inserting a multiple turn coil in said stator comprising: a base portion and a head portion; said base portion having a substantially circular cross sEction in a first plane and having means associated therewith for attachment to a coil placing device; said head portion also having a plurality of parallel elongated members disposed on the circumference of a circle, the plane of the circle being parallel to said first plane for maintaining the relative orientation of at least some of the individual turns of a coil during the insertion process said elongated members mounted on said head portion each being positioned radially inwardly of a corresponding fixed elongated member on the machine.
 4. The coil stripper of claim 2 wherein said elongated members are removably affixed to said head portion.
 5. The coil stripper of claim 2 wherein said head portion further comprises a portion interior said elongated members which is provided with a plurality of slots which serve to connect specified pairs of gaps.
 6. The coil stripper of claim 2 wherein said elongated members are attached to said base portion in cantilever fashion further comprising removable alignment means adapted to maintain the separation between said elongated members remote from the point of cantilever attachment.
 7. The coil stripper of claim 5 wherein said elongated members are attached to said base portion in cantilever fashion further comprising removable alignment means adapted to maintain the separation between elongated members remote from the point of cantilever attachment.
 8. The coil stripper of claim 3 wherein said elongated members are removably affixed to said head portion.
 9. The coil stripper of claim 3 wherein said base portion has a plurality of radially extending fins each lying in a plane which is perpendicular to said first plane, said fins being so disposed that the edge of a fin forms a radially outward extension of the gap between two adjacent elongated members. 